I looked though this forum and couldn't find a way to disable the beep that goes with the keyless entry. I found it on a youtube video. Went out and disabled the beep in about 30 seconds.
This should work from a minimum of 2005 to at least 2010. Not sure about 2011-2013.

Step one: Keep driver side door open. Insert key into ignition and take out.
Step two: Put key back in ignition w/in five seconds. .
step three: Turn to the "on" position, not the acc position and wait 10 seconds.
Step four: click the "lock" or "unlock" twice as soon as the key is in the "on" position. You should here one continous beep for about a second.
Step five: Take key out. Get out of truck. Shut door. Try your keyless entry button. You should get no beep but still see the parking lights flash.